The Book of Faith (Kitab Al-Iman)
Muslim :: Book 1 : Hadith 174
The same hadith has been transmitted by the same chain of narrators. The hadith transmitted by Auza'i and Ibn Juraij contains these words: I embraced Islam for Allah's sake. and in the hadith narrated by Ma'mar the words are: I knelt down to kill him, that he said; There is no god but Allah.